Method and apparatus for monitoring contaminants in a fluid flow

ABSTRACT

An apparatus and method is disclosed to monitor the condition of a fluid flow including particulate matter and air or gas content fluid in the fluid flow as well as fluid quality. The apparatus includes a sensor array with an ultrasonic transducer, inductive sensor and fluid quality sensor. It also includes a cyclonic separator. The method includes sensing and sizing particulate matter, distinguishing air bubbles from the particle matter and assessing the quality of the fluid.

This application claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Application Ser. No. 62/042,910 filed on Aug. 28, 2014entitled “Method and Apparatus for Monitoring Particles in a FluidFlow”, and U.S. patent application Ser. No. 14/523,815 filed Oct. 10,2014 entitled “Method and Apparatus for Monitoring Particles in a FluidFlow” the content of both of which are relied upon and incorporatedherein by reference in their entirety.

FIELD OF INVENTION

The present invention provides an improved method to enable on-linehealth monitoring of a fluid circulatory system to determine thecondition of the fluid and maximize equipment life. The technologies arebased on ultrasonic, inductive and fluid quality sensors and arefunctionally-integrated into a compact sensing cluster for monitoringthe entire fluid flow volume.

BACKGROUND OF INVENTION

Critical machinery increasingly requires that the lubrication system ismonitored real-time for indicators of mechanical as well as fluiddegradation. Because external factors have an extensive influence on thelubricant during operation, knowing the particle size distribution andmaterial properties of the contamination plus other properties relatedto lubricant quality such as water saturation, enables the user toevaluate the precise condition of the system. For example, themechanical components of a helicopter gearbox operate under extremeload, speed and environmental conditions causing rotating component wearthat can progress very rapidly to result in a sudden, catastrophicfailure. Corrosion precursors, especially water, significantly affectmaterial strength properties in gearbox components, thereby reducing thecomponent's load carrying capacity and ultimately shortening its usefullifetime. Bearing failures often cause reliability issues and can causecatastrophic failures of the entire system. Real time sensors canprovide the capability to continuously monitor the lubricant flow todetect the onset of a premature failure and provide for safe shut down.On-line sensors can trend wear debris size and the rate of production aswell as identify corrosion precursors. This capability will improvemaintenance action and component replacement recommendation, thusincreasing asset readiness and reducing total ownership costs.

Engine and gearbox wear is commonly monitored using magnetic chipdetectors placed directly in the oil flow that can detect metallicparticles approximately 200 μm in size and greater. Inductive sensorsare available for detection of both ferrous and non-ferrous metals aswell. However, these methods cannot detect non-metallic wear debrisparticles. This poses a limitation since new high performance engineshave begun to utilize new materials and ceramic bearings that offerconsiderable weight savings, and thus increased fuel efficiency.Obviously, legacy health monitoring systems using magnetic or inductivesensors are not capable of detecting the failures of these non-metallicmaterials.

Hence there is a need to monitor the health of these non-metalliccomponents. Also, it is desirable to be able to monitor all of thecirculating fluid (oil), not just a portion of it, to ensure that allthe larger more serious wear debris particles are detected. As a generalrule, the larger the particle size, the more serious the potentialfailure condition, but correspondingly occur more rarely. A samplingstrategy is not appropriate to address the rarely occurring largerparticles. Thus, all of the oil flow must be monitored; an in-linesystem for monitoring is the best option. In addition, there is also aneed to monitor the lubricant quality such as water saturation whichaccelerates the aging process of metallic engine components.

Prior art technology does not address all the above requirements. Anumber of patents and papers relate to acoustic monitoring of fluidflow. A method of this type is disclosed in British Patent 1,012,010(1963) which describes a method and equipment for counting and measuringparticles in various measurement zones along the acoustic axis of anultrasonic transducer in the suspension. By using suitable time windowswhen receiving the reflected acoustic signals, the particles in apredetermined number of measurement zones are counted. By making use ofa different threshold voltage for each time window, a minimum size forthe particles to be counted is selected for each zone. Assuming that theparticle distribution is the same in each zone, and only one particle iswithin the measurement zone, a rough estimate of the number ofparticles, subdivided according to particle size is obtained.

Other systems characterize the type and shape of particles in thesuspension by evaluating the angle-dependent reflection behavior of theparticle. U.S. patent Ser. No. 04/381,674 (1983) and 04,527,420 (1985)describe a bistatic arrangement for target material identification onthe basis of the ratio of the outputs of two transducers. U.S. patentSer. No. 04/339,944 (1982) covers particle discrimination on the basisof comparing spectral characteristics of the reflected pulse withpreviously acquired spectra of known particles. This is also describedin Nemarich, C. P., J. C. Tuner, and Whitesel, H. K., “Evaluation of anOn-Line Ultrasonic Particle Sensor Using Bearing Test Data”, 41^(st)Meeting of the Mechanical Failures Prevention Group, Patuxent River, Md.(1986). In U.S. Pat. No. 6,205,848 (2001) a large measurement Volume isdescribed such that the angle of incidence varies as a function of thelateral position. If a particle in the flowing suspension is exposedvarious times in succession by an acoustic signal, the successivereflection signals differ as a consequence of the angle-dependentreflection.

Prior work using ultrasonic transducers for wear debris measurementsperformed by Innovative Dynamics Inc. [(1) Edmonds, J., M. Resner, andK. Skharlet, “Detection of precursor wear debris in lubricationsystems”, IEEE, 2000; (2) Edmonds, J., J. Gerardi, G. Hickman,“Helicopter/Tiltrotor Gearbox Debris Monitoring”, Navy SBIR Phase I IDIFinal Report, 1995) has shown the ability to measure particles down to 5um in diameter, and when combined with inductive sensors provides fullspectrum wear debris monitoring capability, allowing one skilled in theart to be able to identify and differentiate both metallic and nonmetallic wear debris particles.

These methods all use focused ultrasonic transducers to estimate theparticle concentration and the particle size distribution based onstatistical sampling of the flow. These methods are limited by the shapeof the acoustic beam and only a partial volume of the fluid that passesby the transducer is monitored. Particles outside the focus region,including larger size particles indicative of impending failure, cantherefore not be detected. Also, while some of these methods candifferentiate air bubbles and solid particles because they have distinctspectral shapes, these methods do not currently sample fast enough todetect all debris if the flow rate or debris concentration is relativelyhigh, thus requiring complex high speed sampling hardware. Although anultrasonic transducer responds to all solid debris and current designsare unable to reliably differentiate between metallic debris andnon-metallic debris, air bubbles, or water.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a collimatedultrasonic method for the real time monitoring of contaminants in afluid that is capable of identifying the number and size of debrisparticles by acoustic means, the type of material by electromagnetic orinductive means and the lubricant quality by capacitance means.

It is another objective of this invention to detect and measure all weardebris particles generated in a system by sampling a representativefluid volume, as opposed to statistical sampling methods that focus on arelatively small sample volume that do not necessarily measure all weardebris particles in the fluid or lubrication system.

It is another objective to determine the basic material type of thedebris particle sized from approximately 10 μm and greater in order todetermine whether it is metallic (ferrous or nonferrous) or nonmetallic(ceramic) as to infer wear status of all critical internal systemcomponents that the lubricant contacts.

It is another objective to provide a means to mitigate the presence ofair bubbles in the sensing zone of the ultrasonic sensor and to discernthe difference between solid particles and air bubbles as to insureagainst false positive sensing events.

It is another objective to monitor the lubrication fluid quality toenable on-condition maintenance rather than based on standardinterval-based maintenance. Moreover, the fluid is monitored formoisture content and oxidation.

It is another objective to separate out and ultimately collect all weardebris particles above a threshold size (typically 10 μm), and providean access port to collect them for verification.

It is another objective of the invention to analyze the acousticsignature response of the fluid to record the amplitude of each particlethat arises in the flow (typically in the size range of 10 μm andgreater) and time stamp each of them.

It is another objective to provide redundancy for particle sizeestimation, by means of two different sensing technologies (acoustic andinductive), as well as multiple sensor readings (acoustic) of the sameparticle.

It is another objective to provide a collimated ultrasonic sensor with afield of view wide enough such that multiple sampling events can beperformed on a target. Moreover, this would allow the capability to moreaccurately size the particle and also discern multiple particlesfollowing closely in succession. A focused transducer could potentiallybe used to sense particles significantly smaller than 10 μm; however ithas a narrow field of view and therefore could miss particles in theflow.

It is another objective of the invention to use the ultrasonic sensor inconjunction with an inductive sensor to distinguish between metallic(ferrous and non-ferrous) and nonmetallic (ceramic) particles.

It is another objective of the invention to integrate sensors with acyclonic phase separator to separate debris particles from the flow (theair bubbles remain with the flow) and sequester the particles through acollection port into a sensing module such that contaminant measurementscan be sampled at speeds independent of the flow rate.

It is another objective of the invention to merge the technologies ofdebris monitoring (ultrasonic and inductive sensors) and oil qualitymonitoring using multi-sensor data fusion techniques such as neuralnetworks or fuzzy logic to enable a comprehensive prognostic healthmonitoring system. In this approach, multiple sensor data is used alongwith known trends in lubrication failures to diagnose the oil conditionand to predict the remaining useful life of mechanical components suchas gears and bearings.

It is another objective of this invention to monitor the particulatedistribution of food and beverages such as wine and coffee for qualitycontrol purposes.

The inventions described herein accomplish the above and other objectsby providing a sensor array for detecting objects in a fluid flowhaving: a) an ultrasonic sensor with its transmission axis positioned atan oblique angle to an axis of fluid flow with a reflective surfacepositioned on an opposite side of the axis of the fluid flow in aposition normal to the transmission axis of the ultrasonic sensor tothereby reflect transmissions from the ultrasonic sensor back to theultrasonic sensor and wherein the oblique angle creates a field of viewfor it to interrogate with a plurality of ultrasonic pulses acousticallyreflective objects and determine direction and size; b) an inductivesensor positioned along the axis of fluid flow adjacent the ultrasonicsensor; c) wherein the ultrasonic sensor determines if an object is asolid particles and an air bubble; the inductive sensor determines if ametallic particle is ferrous or none ferrous and both sensors workingtogether identify nonmetallic particles; and d) wherein the ultrasonicsensor distinguishes between solid particles and air bubbles based onorientation of the sensor array to a local gravitational field.

In another aspect of the sensor array the adjacent position of theinductive sensor is along the axis of fluid flow downstream from theultrasonic sensor. In yet another aspect of the sensor array the axis offluid flow can be in a downward direction in a gravitational field. Inyet another aspect of the sensor array it can include a fluid qualitysensor to determine one or more conditions of a fluid in the fluid flow.In yet another aspect of the sensor array the fluid flow can be an oilcirculating system and the fluid quality sensor is an oil quality sensorthat assess water content and oxidation of the oil. In yet anotheraspect of the sensor array it can monitor a fluid flow of fluids thatcirculate: beer, wine, milk, ice cream, water, or soda. In still yetanother aspect of the sensor array the oblique angle at which theultrasonic sensor axis is positioned at can be in an upward facingposition with respect to the local gravitational field. In still anotheraspect of the sensor the oblique angle is an angle between thetransmission axis of the ultrasonic sensor and a path of a particlefalling through fluid of the fluid flow. In yet another aspect of theinvention the sensor array can have an oblique angle that varies from89° to 0°. In another aspect the sensor array the oblique angle isoptimally 45°. In yet another aspect of the invention the sensor arraybecause of its oblique angle to the axis of fluid flow can interrogateparticles with multiple pulses.

In yet another aspect of the invention it has an ultrasonic transducerhaving: a) a first ultrasonic transceiver and a second ultrasonictransceiver; b) positioning structure for holding the first transceiverin relation to the second transceiver so they have congruenttransmission and reception paths but are physically and acousticallyseparated from each other by the positioning structure; c) an acousticdampening structure connected to the first transceiver and an acousticdampening structure connected to the second transceiver; and d) acontroller functionally connected to the first transceiver and thesecond transceiver for activating and controlling operation of the firstand second transceiver.

In another aspect of the ultrasonic transducer the first transceiver canbe disk shaped and the second transceiver can be ring shaped, and thesecond transceiver can surround the first transceiver. In yet anotheraspect of the ultrasonic transducer can have a positioning structureholding the first and the second transceiver is an acoustic lens withpockets into which the first and the second transceivers fit. In yetanother aspect of the ultrasonic transducer one of the transceivers canbe used solely for transmission of ultrasonic pulses and one of thetransceivers can be used solely for receiving ultrasonic pulses and thetransceiver used solely for transmission has a large acoustic dampeningstructure attached to it to enhance acoustic dampening and thetransceiver used solely for receiving has a smaller acoustic dampeningstructure attached to it to increase its sensitivity to a receivedsignal. In yet another aspect of the ultrasonic transducer the acousticdampening structures can have an end distal from the transceiver ashaped surface to deflect ultrasonic pulses.

In another aspect of the invention it provides a cyclonic separator forseparating particulate matter from a fluid flow having: a) an interiorchamber in a shape of a truncated conic section, the truncated conicsection being formed by a top, a continuous wall and floor that form aninverted pie plate shaped interior chamber, wherein a circumference ofthe top is smaller than a circumference of the bottom; b) an inlet portinto the interior chamber through the wall offset from a center axis ofthe truncated conic section; c) an outlet port at the top of thetruncated conic section; d) an open top closed circuit collectionchannel in the floor; and e) a collection port in the collection channelto thereby create fluid communication from the interior chamber to asensor array.

In another aspect of the invention the cyclonic separator the collectionport can extend through the floor to thereby connect to the sensorarray. In yet another aspect of the invention the cyclonic separator thecollection port can be formed by a tangential extension of the collectorchannel, the collector channel extending through the wall to therebyconnect to a sensor array. In yet another aspect of the invention thecyclonic separator the outlet can be positioned in a center of the topso that a center axis of the outlet is congruent with the center axis ofthe truncated conic section and the outlet can be formed by a flowdivider with a deflector mound positioned on the floor directly belowthe outlet. In another aspect of the invention the cyclonic separatorthe inlet port can be formed by a circular opening at a first endexterior to the interior chamber with a channel from the first openingthrough the wall of the interior chamber to a second opening where thesecond opening is elliptical in shape and the channel provides fluidcommunication from the from first opening to the interior chamber. Inyet another aspect of the invention the cyclonic separator a crosssectional area of the channel from the first opening to the secondopening can have substantially the same and the channel is on a tangentto a curvature of the wall of the interior chamber. In another aspect ofthe invention the cyclonic separator is formed as a unity structure ofsubstantially one material with no seams or joints. In yet anotheraspect of the invention the cyclonic separator it is fabricated by a 3-Dmanufacturing process to create its single unitary structure.

In yet another aspect of the invention it provides a method formonitoring and analyzing the condition of a fluid flow, which includesthe steps of: a) separating particulate matter from a primary fluid flowchannel; b) directing objects in the fluid flow to a sensor array sothat the objects pass-along a predetermined path; c) interrogating apredetermined field of view along the predetermined path with aplurality of ultrasonic pulses directed along an axis of transmission atan oblique angle to the predetermined path and receiving reflections ofultrasonic pulses from the objects wherein the reflections of ultrasonicpulses are on an axis of reception congruent with the axis oftransmission of the ultrasonic pulses; d) generating an inductive fieldalong the predetermined path; e) distinguishing air bubbles fromparticulate matter among the objects detected based on a receivedplurality of reflections; f) determining a size of the objects; g)determining if the particle is metallic or non-metallic by combiningreadings from the ultrasonic reflections and inductive filed readings;and h) determining if a metallic particle is ferrous or non-ferrous fromthe inductive field readings.

In another aspect of the method of the invention it includes the furtherstep of determining the condition of the fluid. In yet another aspect ofthe method of the invention the fluid flowing being monitored can beselected from a group of fluids consisting of: beer, wine, milk, icecream, water, or soda.

In another aspect of the invention it provides a method for training aneural network for identifying failure conditions in a fluid circulationsystem comprising the steps of: a) monitoring a fluid circulation systemwith a set of sensors; b) generating a history of raw sensor signals ina time dependent basis of the fluid flowing in the fluid circulatingsystem for a broad range of known good and bad conditions; c) extractinga set of pertinent fluid parameters or features from the sensor signalsregarding: i) particles material, size, count and distribution in thefluid circulating in the system; ii) particle distribution change rate;iii) undissolved air in the circulating system; iv) water content; v)fluid temperature; vi) oxidation; d) inputting both the features andknown fluid condition into the network (training set) to train a set ofweighted connections to handle those particular failure modes.

In an another aspect of the method of training a neural network the stepof gathering sensor signals comprises gathering sensor signals form thefollowing sensors: a) an ultrasonic transducer, b) an inductive sensor,c) a fluid quality sensor, and d) a temperature sensor. In yet anotheraspect of the method of training a neural network the step of monitoringfluid circulation is monitoring a system wherein the fluid flowing inthe fluid circulating system is selected from a group of fluidsconsisting of: oil, beer, wine, milk, ice cream, water, soda, coffee,espresso, chocolate and coco.

The accompanying drawings are included to provide a furtherunderstanding, and are incorporated in and constitute a part of thisspecification. The drawings illustrate one or more embodiment(s), andtogether with the description serve to explain principles and operationof the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts one variation of the invention which shows an axialcross section of a cyclonic separator with an embodiment of the sensorcluster of the present invention;

FIG. 1B shows a radial cross-section of cyclonic separator of FIG. 1Aalong line IB-IB of FIG. 1A;

FIG. 2A depicts an axial cross-sectional cut-away view of a secondembodiment of the sensor cluster of the present invention;

FIG. 2B is a cross-sectional view of the sensor cluster of FIG. 2A alongline IIB-IIB;

FIG. 3A is a graph of an ultrasonic sensor pulse echo receiver responseshowing the pulse echo shift for particles or bubbles of air detected;

FIG. 3B is a graph of a series ultrasonic pulse echo's reflected off ofthe same particle as it moves through the field of view of the sensor;

FIG. 3C is a graph of pulse echo's reflected off of particles of twodifferent sizes at two different times as the particles move through thefield of view of the sensor;

FIG. 4A is a cross-sectional cut-away view of an ultrasonic transducerof the present invention along its axial view;

FIG. 4B is a cross-sectional view along lines C-C of FIG. 4A;

FIG. 4C is a cross-sectional cut-away view of another embodiment of anultrasonic transducer of the present invention;

FIG. 4D is a cross-sectional cut-away view of another embodiment of anultrasonic transducer of the present invention;

FIG. 4E is a cross-sectional cut-away view of another embodiment of anultrasonic transducer of the present invention without a transducerlens;

FIG. 4F is a view of the end of the embodiment of the ultrasonictransducer depicted in FIG. 4E without a transducer lens;

FIG. 5 is a simple flow chart that summarizes one preferred method thepresent invention uses to analyze data collected by the various sensors;

FIG. 6 provides a top view of a preferred embodiment of a cyclonicseparator of the present invention with a partial cut-away view of theinterior;

FIG. 7 an axial cross-sectional view of the cyclonic separator of FIG. 6along line VII-VII;

FIG. 7A is a sectional view VIIA of FIG. 7;

FIG. 8 provides a top view of another variation of a preferredembodiment of the cyclonic separator of the present invention with apartial cut-away view of the interior and attached sensor array;

FIG. 9 is cross-sectional axial view along line IX-IX of FIG. 8;

FIG. 10 is sensor output histogram of information generated by thesystem and apparatus of the present invention; and

FIG. 11 is an example of a possible aircraft output display on anaircraft that uses the method, system and apparatus of the presentinvention.

DETAILED DESCRIPTION

A First Embodiment of the Sensor Cluster:

FIG. 1A is an axial cross-section of one embodiment of the inventionthat employs a cyclonic separator 100 with three types of fitted sensorsin sensor array 110 for the detection of debris particles in a fluid aswell as determine the quality of the fluid itself. A Cyclonic separator100 is utilized to separate debris particles from a 3 phase fluid flowconsisting of fluid, air, and debris particles. The fluid flow entersinto inlet port 104 and due to the inlet ports configuration as depictedin FIG. 1B with inlet port 104 offset from the axial center 107 ofcyclonic separator 100 induces a strong Cyclonic flow 106. Ultrasonictransducer 112, inductive sensor 114 and oil sensor 116 make up sensorcluster 110.

Referring back to FIG. 1A the cyclonic flow 106 causes all particlesabove a threshold size to displace radially outward to the Wall 108.Given the characteristics of the fluid and rate of fluid flow, particlesas small as 100 microns or less will be urged towards the wall 108 ofseparator 100. The fluid and air bubbles pass out the outlet port 109and the separated particles which have been dispersed out towards wall108 of separator 100 fall by gravity to the base of the separator 100near watt 108 and eventually fall into sensor cluster 110 throughopening 111 where the sensors determine the physical properties of thewear debris particles, as described below. Hence due to gravity the weardebris particles 102 drop through sensor array channel 117 past thesensing zones of ultrasonic sensor 112, inductive sensor 114 and oilquality sensor 116 into a collection trap 130. The collection trap 130contains and stores all particles separated from the flow and can laterbe removed and analyzed at servicing intervals. The fluid in sensorarray channel 117 is substantially still or stagnant since the sensorarray channel dead ends at collection trap 130.

Transducer 112 and sensors 116 and 114 all connect to a computer andpower supply 137 by lines 138, 139 and 140 in a standard fashion forcontrol and function. Computer 137 would be programmed in a standardfashion to control operation of sensors 116 and 114 as well astransducer 112 to obtain appropriate data and analyze it.

Ultrasonic transducer 112, which will be described in detail below, ispositioned to transmit ultrasonic pulses towards oil quality sensor 116front surface 135 which front surface presents a flat surface normal tothe axis of transmission of transducer 112 for the ultrasonic pulsegenerated by the transducer to bounce off. Given that the frequency ofthe ultrasonic pulse generated is known and controlled by the operatorand the time it will take the pulse to travel to and from reflectionsurface 135, if a particle falls into the field of view of ultrasoundtransducer 112 it will reflect back a portion of the ultrasonic wavebefore the main portion of the wave is reflected from surface 135 backto transducer 112. Thus, with this first reflection off of the particleor alternatively an air bubble, transducer 112, which is connected tocomputer 137 will start the process of determining if a particle or airbubble is present. Since transducer 112 generates a series of pulses ina time sequence during the time that the particle or air bubble will bein the field of view of transducer 112 the system can determine if thereflection is from an air bubble or a particle. With each pulse the airbubble will be moving up in the liquid and the particle will be movingdown. Because transducer 112 is positioned at an oblique angle Θ 120with respect to the path of the particle or air bubble, given thedownward projection of the axis of transmission 121 of transducer 112the sound reflection or echo as the result of a subsequent pulse from anair bubble will indicate it is closer since it will be rising in thefluid. On the other hand if second sound reflection or echo indicatesthe item reflecting the pulse is further away it will indicate it is aparticle. This process will be explained in more detail below.

Oil quality sensor 116 is mounted as noted in FIG. 1A in a site nearultrasonic sensor 112 in a manner that is the most compact andsimplifies manufacturability. Oil quality sensor 116 monitors variousfluid qualities that could be of interest to machinery healthmaintenance. For example, if the fluid is oil it would monitor watercontent and oxidation of the oil. In the preferred embodiment of thepresent invention oil quality sensor 116 uses a capacitive based sensorbuilt into its face 135 to monitor the condition of the oil. However,those skilled in the art will readily see that the present invention canbe built with various fluid monitoring sensors to monitor conditions ofa large number of different fluid circulating systems. Also, oil qualitysensor can be positioned in a different location and a separate targetsurface would be provided at 135 for transducer 112.

Inductive sensor 114 is a standard type of inductive sensor. It consistsof an inductive coil attached to appropriate circuitry, not shown. Instandard fashion when a metallic particle falls through the center ofinductive sensor 114, the sensor detects its presence and based on thesignal generated by the coils the system can determine if it is aferrous or non-ferrous metallic mass. On the other hand if the particleis nonmetallic inductive sensor 114 will not detect its presence as itfalls through the field generated by the inductive coil. However sincethe inductive sensor 114 is positioned adjacent to transducer 112, inthis embodiment downstream from the transducer, the systems computer 137can be programmed to time stamp the particle detected by transducer 112and then look for the particle as it passes through the inductivesensors coil and if inductive sensor does not detect the presence of theparticle when it should be passing through the field of the inductivesensor it determines the particle is nonmetallic. As an alternative theinductive sensor can be located upstream from the transducer and thesystem can still function in the same manner to distinguish metallicfrom non-metallic particles.

Ultrasonic sensor 112 and inductive sensor 114 as noted above are usedcollectively to detect and identify metallic debris and non-metallicdebris. Neither sensor type alone can perform this function. Ultrasonicsensor 112 can detect metallic and non-metallic particles but cannotidentify the material type. Ultrasonic sensor 112 can also determine ifthe particle is in fact an air bubble. Inductive sensor 114 can detectand distinguish between ferrous and non-ferrous metallic particles, butcannot detect non-metallic particles such as ceramic particles.

Thus as noted after a particle falls through the field of view oftransducer 112 and it determines it is a particle and not an air bubbleit will next fall through the induction field of inductive sensor 114.If the debris particle is metallic, sensor 114 will sense it and basedon the signal generated computer 137, which will be programmed to do so,will determine of it is ferrous or non-ferrous based on the signal ornon-signal from inductive sensor 114. If the particle is non-metalliccomputer 137 will determine this fact since the computer will beprogrammed to expect the particle in the field created by sensor 114 andthe fact it cannot detect it will indicate it is non-metallic.

To prevent air bubbles from collecting on the face 141 of transducer 112beveled edge 143 starts adjacent to face 141 of the transducer andslopes upward thus allowing air bubbles to move upward and away fromface 141 and not collect on the face of the transducer. If air bubbleswere to collect on the face of transducer 112 it would degrade operationof the transducer to the point it would be ineffective.

Collection Trap 130 has a funnel shaped flange 132 that retainsparticulate matter 102 that falls into trap 130 if for some reasonsensor array 110 is tipped to the side or moved in a reversedgravitational field. Thus, the present invention can be used onaircraft, including fighter aircraft or helicopters as part of the oilcirculating system where certain maneuvers of the aircraft, such assteep banking turn or a roll of the craft creates a reserve flow offluid, in this case oil out of trap 130. Flange 132 helps retain theparticles during such maneuvers. Additionally, cap 133 of trap 130 canbe magnetized to help retain ferrous metallic particles.

The apparatus is suitable for handling large flow rates without causingunnecessary back-pressure in the oil system line. The close mountingproximity of all three sensors provides an advantage since their accesscabling can be routed together and connected to the same electronicspackage. Transducer angle Ø 120 as defined between ultrasonic sensorAxis 122 and debris path 124 provides a significant performanceadvantage for ultrasonic sensor 112 for detecting and sizing particlesas will be noted below.

A Second Embodiment of the Sensor Cluster:

FIG. 2A is a cross-sectional view cut away of another embodiment 207 ofthe sensor cluster of the present invention. Opening 111 from thecyclonic separator is at the top. In this embodiment the top portion hasa funnel 210. Transducer 212 is aligned along axis 223 with oil qualitysensor 216 with transducer 212 transmission face 241 oriented along axis223. Axis 223 forms an oblique angle θ 220 with center channel axis 221of sensor cluster 207. Inductive sensor 214 is located at the bottom endof sensor cluster 207 structure.

FIG. 2B is a cross-sectional cut away view along line IIB-IIB which isat 90° to the view depicted in FIG. 2A. Since transducer 212 is orientedand in an upward facing direction along axis 223 and has a flattransmission surface 241 the ultrasonic pulse it generates is reflectedoff of the face 251 of oil detector 216 back towards transducer 212. Theface 251 of oil quality sensor 216 is normal to axis of transmission 223of transducer 212. Since the ultrasonic wave generated by the pulse is aroughly cylindrical shape as will be discussed below, the wave covers anelliptical area 253 FIG. 2B from point 261 to 263 along central axis 221of sensor cluster 207, see FIGS. 2A and 2B forms the field of view (FOV)of sensor 212.

Thus debris 102 falling through opening 111 into sensor cluster 207 willbe directed by funnel 210 along the central axis 221 of sensor cluster207 arranged along sensor array channel 217 and be subject to detectionby pulses from transducer 212 from point 261 to point 263. The fluid orliquid in sensor array channel 217 which ends in collection trap 230 issubstantially still and stagnant.

As noted field of view 253 resembles an ellipse with its major axisaligned with the direction of the target movement (whether up or down).Funnel 210 directs debris particle 102 along central axis 221 such thatit remains in the field of view 253 for an extended duration. Thisenables ultrasonic sensor 212 to interrogate the particle with severalpulses of ultrasonic sound to determine its direction and size. Withoutfunnel 210 a particle could fall down along the wall 255 of the passagethrough the sensor cluster 207. This would result in a shorter dwelltime within the field of view 253. The shorter dwell time could resultin the particle passing by the ultrasonic sensor 212 without beingdetected or only being pinged by one pulse. Moreover, the sensingstrength is potentially at a maximum and substantially uniform alongaxis or path 221. An effective angle 220 is about 45 degrees. But asoblique angle 220 can be varied from about 0° to 75° or greater byvirtue of design requirements. With angles less than 45° the ellipsebecomes more eccentric, thus further extending the effective field ofview length and thus increase the number of potential sensing events.With angles larger than 45° the ellipse becomes less eccentric and morecircular and in fact the closer it approaches 90° its ability to detectmovement diminishes, this aspect will be discusses below in a littlemore detail. With angles smaller than 45° the logical extreme is tomount sensor 212 at 0° or in the position of plug 235 (without obstacle232) to provide an unobstructed FOV to the falling wear debris. In thiscase the targets can be viewed with the maximum potential number ofsensing events as they approach the transducer lens. However, in thiscase particles can collect on face 241 which could be detrimental. Otherdesign features to collect and trap particles would be added by oneskilled in the art to keep face 241 flushed of debris buildup. Thus,funnel 210 by directing movement of particles along axis 221 helpsenhance the accuracy and effectiveness of the sensor array 207.Directing the particles along or substantially along axis 221 thusresults in a uniform or substantially uniform reflected signal which inturn significantly increases the accuracy of the system. However, in thepreferred embodiment an angle 220 of about 45° is optimal, but someapplications might use different angles depending on the systems use.

Given ultrasonic sensor axis 223 mounting angle, wear debris particle102 is first detected with first particle echo or reflection as itenters the field of view 253 of the ultrasonic transducer 212, at point261. As the particle falls through field of view 253 of transducer 212it will be pinged multiple times sending back an echo or reflectedultrasonic wave. The multiple reflected signals will thus confirm theparticles downward movement due to the forces of gravity since the solidparticle is denser than the fluid. Given the orientation of thetransducer in this embodiment of the invention with each successive(ultrasonic) ping and reflected pulse the particle will appear to getcloser to the transducer until it moves out of the field of view of thetransducer.

In contrast, as previously noted an air bubble will rise due to itsbuoyancy. This will be detectable by this embodiment of the inventionsince the air bubble appearing to move further away from transducer 212with each successive pulse while the air bubble is within the field ofview of transducer 212. Thus, the positioning of the transducer allowsit to determine if the item detected is moving up such as an air bubblesor down such as a particle. If Ultrasonic transducer 212 were ratherconfigured with ultrasonic sensor axis perpendicular to the debris pathaxis no such capability would result. Most of the air bubbles flowing inthe fluid within the separator will not enter into sensor array 207.However, a fluctuating pressure environment or due to other causes, airbubbles can precipitate in the fluid in the cavity within the sensorarray.

Another advantage of the configuration created by transducer angle Θ 220is that some debris particles can have a plate-like shape, rather thanhaving a spherical or other shape with a low surface area to volumeratio. Such plate shaped particles can fall through a stagnant fluidwith its flat side perpendicular to the movement. The oblique angle oforientation results in the particle presenting a more substantialprojected area to the pulse generated by ultrasonic transducer 212 thanif the sensor were mounted with ultrasonic sensor axis orientedperpendicular to axis or debris path. The return signal strength ofultrasonic transducer 212 is strongly proportional to an area exposurefactor. If ultrasonic transducer 212 were rather configured withUltrasonic sensor axis perpendicular to the debris path axis no suchcapability would result.

Ultrasonic transducer 212 in this embodiment is mounted with an upwardcant at oblique angle Θ which prevents air bubbles from collecting inthe immediate vicinity of the transmission face 241. In contrast,bubbles can rise and stick momentarily to downward canting surfaces suchas face of oil quality sensor 251. The air bubbles will rise naturallyaway from an upwards canting surface such as 241, than if it were canteddownwards as described in the previous embodiment. The presence of anexcess quantity of gas bubbles can attenuate or completely block thesignal of ultrasonic transducers. Moreover, the upwards cantedconfiguration of all interior surfaces in the sensor array thus enablebubbles to rise upward and eventually purge through funnel 210.

Oil quality sensor 216 is not inordinately affected by bubbles. Thesensor needs only to be exposed to the fluid and be in close proximityto the main flow such that the fluid characteristics that it monitorsdiffuse quickly to it. The downward canting orientation guarantees thatno debris can be trapped within it. Oil quality sensor 216 is made witha smooth planar face 251 that faces transmission face 241 of ultrasonictransducer 212. Face 251 of sensor 216 provides surface for a specialreturn signal that defines the acoustic space between it andtransmission face 241 of transducer 212 and provides a calibrationmarker for the system. The calibration marker defines the acousticspace, enables the system to perform a preliminary diagnosis, and aidsin particle size estimation. Ultrasonic transducer 212 is mounted with asuitable mechanical method such as threading its outer case intomounting boss and sealing with a polymer seal according to conventionalmethods. Likewise, Oil quality sensor 216 attaches to a mounting bossand can be sealed in a similar manner.

Debris particle 102 also falls through magnetic field of spiralinductive coil 214. Coil can be powered through voltage plus, andvoltage minus. If a metallic particle enters the field, a measurableinductance change occurs and can be calibrated to particle size andwhether it is ferrous or non-ferrous.

Although FIGS. 2A and 2B do not include computer 137 and connectinglines 138, 139 and 140, their exclusion is only to provide anuncluttered view of the embodiment depicted in both drawings. Inoperation the system shown in FIGS. 2A and 2B would include a computerand connections via lines or wireless system when installed.

Detection:

FIGS. 3A, 3B and 3C provide a graphical representation of the variousreflected signals that the transducers 112 and 212 receive in responseto Ultrasonic interrogation pulses with reflections or echoes fromtargets in the acoustic field of view. The y-axis represents theamplitude of the wave and the x-axis represents the distance the objectreflecting the wave is from the transducer with the transducer beinglocated at zero on the x-axis and y-axis.

Referring to FIG. 3A, 314 is ring down acoustic behavior internal to thetransducer, of reverberations, or ring down, from the interrogationpulse generated by transducer 112 or 212. 316 is the reflection of theinterrogation pulse off of the face of oil quality sensor 116 or 216respectively. 310 is the first echo received when a particle or airbubble enters the field of view of the transducer at time T₁ which is areflection of the interrogation pulse generated by the transducer. 311and 312 are subsequent echoes reflected by a particle from a subsequentor second pulse generated by the transducer at a subsequent time T₂. Asnoted above transducers 112 and 212 generate periodic pulses at presetintervals. These intervals can typically be 3 milliseconds apart;however the pulse intervals can be varied depending on the applicationand need.

Transducer 112, given its position and the angle of its axis, thesubsequent echo or reflected pulse 311 received at time T₂ being closerto transducer 112 would indicate that the object is rising and thus anair bubble. On the other hand if at time T₂ reflected pulse 312 appears,this indicates the item has moved further away from transducer 112 thusindicating it is a particle moving down through the fluid.

With respect to transducer 212, given its position the opposite would bethe case. After a first pulse at time T₁ with the item generating areflected signal at 310, if at time T₂ the second reflected signal is at311 it would indicate that it is a particle failing down through thefluid since second signal 311 indicates it is closer to transducer 212than the first pulse 310 received at time T₁. On the other hand if thereflected signal indicates the item reflecting is at 312 it wouldindicate the item is moving away from transducer 212 and thus is an airbubble rising in the fluid.

Whether a Debris particle 102 or an air bubble is in the field of viewof one of the transducers or not, the interrogation pulse propagatesuntil it hits the face of the oil quality sensor and generates back wallreflected wave 316. Back wall wave signal 316 is used to determine thestrength of the interrogation pulse and proximity of targets forcalibration purposes. The physical distance from the origin to 316 inthe preferred embodiment corresponds to ½ of the elapsed time. A factorof ½ is imposed since the acoustic wave propagates from transducer face241 to the back wall 251 then returns all of the way back. This is twolengths traveled between 241 and 251. This distance can be calculatedfrom the speed of sound in the fluid.

One of the considerations that the current invention deals with is thering down phase of the initial ultrasonic pulse 314 generated by theUltrasonic transducer. A portion of the initial pulse as noted abovereverberates within the transducer and if not dealt with by appropriatemeans can mask the detection of the reflected signal. The currentinvention deals with this problem by designing the transducer so that itdampens down the ring down of the initial generated pulse. The solutionto this problem will be discussed below with respect to variouspreferred embodiments of the transducer of the present invention. Asaccording to the art for general use of Ultrasonic transducers, the ringdown time zone effectively blocks the practical use of sensing withinclose proximity to the front face such as 241. However, for theembodiments described above, transducers 112 and 212 are set back by anappropriate degree from the target zone which surrounds and is in closeproximity to the intersection of axis 221 and 223. The side of thetarget zone, or a path that a particle can fall, that is closest to thetransducer is set to coincide to just beyond ring down zone 314. Thetransducer is set back no further than this as to maximize the naturalecho signal strength, since the strength diminishes as a function ofdistance due to attenuation caused by the fluid. In the embodiment ofthe invention disclosed the distance from the intersection of axis 221and 223 needs to be about ½″ to ⅝″. However, those skilled in the artwill appreciate the actual distance can vary depending on the system, itsize fluid, etc. Moreover, the transducer as applied to the methods ofthis invention does not have to be as highly damped as is the case withconventional ultrasonic transducers. The primary advantage to this isthat a more sensitive transducer can be designed and used. That is,there is a natural tradeoff between dampening and sensitivity.

FIG. 3B depicts a series of echoes or reflected ultrasonic wavestransducer 212 might receive from the periodic ultrasonic pulses itgenerates. At T1 it receives the first echo from a particle fallingthrough its field of view and at successive times T2, T3, T4 and T5, itreceives successive echoes from the same particle as it falls throughits field of view. FIG. 3C depicts another variation where transducer212 detects two particles of different size falling through its field ofview. At time T1 transducer 212 receives two echoes 330 and 331 and atsubsequent time T2 it receives two pulse additional echoes 332 and 333while the two particles are in its field of view. Echoes 330 and 332would be reflected from the same particle. Likewise echoes 331 and 333would be reflected from another distinct particle. Since the amplitudeof the echoes 331 and 333 are larger than the echoes 330 and 332 itwould indicate the particle reflecting echoes 331 and 333 is larger thanthe particle that reflects echoes 330 and 332. Also, multiple targets ofeven the same size can appear within the transducers FOV during a singleinterrogation pulse and represented by multiple return pulses visible ina single return waveform. Thus it can be discerned whether there aremultiple targets in the field of view, regardless of size. The samelogic can be applied to bubbles and mixtures of bubbles and particles,as introduced above. Particle size is determined from the total energyof the return pulse, calculated from the peak signal amplitude and thepulse-width of the return pulse. Integration of this pulse, plus othersalient waveform features, provide an accurate measurement of particlesize. Also, averaging several results from multiple interrogation of thesame particle, as it drops through the transducer FOV, improves theparticle sizing result.

The Transducer:

FIG. 4A is a cross-sectional interior view of one of the preferredembodiments of a transducer 400 of the present invention. The transducer400 is cylindrical in shape and FIG. 4B is a cross-sectional view alongC-C of FIG. 4A in the direction indicated by the direction of the arrowson line C-C.

Referring back to FIG. 4A transducer 400 has a first crystal transceiver401 which is shaped as a ring and a second crystal transceiver 402 thatis shaped as a disk surrounded by an encasing cylindrical tube 432.Covering the front of crystal 401 and 402 is acoustic lens 412 which hasa flat front surface 416. Acoustic lens 412 attaches at its edge toencasing tube 432 and has pockets 405 and 407 into which crystals 401and 402 fit. Dampening element 424 which has a cylindrical geometricshape attaches to the back of crystal 402. Dampening element 422, whichalso has a tubular geometric shape attaches to the back of crystal 401.Connector 428 is positioned at the back of transducer 400 and connectsby low gauge cable 430A and 430B to transceiver crystal 402 and 401respectively.

Transceiver crystals 401 and 402 in the preferred embodiment arepiezoelectric ceramic material (PZT), lead zirconium titanate. Thepreferred embodiment depicted in FIGS. 4A and 4B because of the flatfront surface 416 of acoustic lens 412 creates a flat circularcollimated sound wave on activation of one or both of the transducercrystals 401 and 402. In the preferred embodiment the biostaticconfiguration of the crystals 401 and 402 calls for one of thetransceivers to transmit an ultrasonic pulse and the other transceiverto receive the reflected or echo ultrasonic pulse. Since bothtransceiver crystals 401 and 402 reside in the same lens assembly 412and thus are aligned along the same transducer central axis (223 FIG. 2Aand 121 FIG. 1A) they are naturally aligned to the same field of view253 as depicted in FIGS. 2A and 2B. Thus one of the PZT elements 401 or402 can be used to transmit ultrasonic pulses and one can be used toreceive the reflected ultrasonic echo or reflection from particle in thetransducers field of view or the planar face 251 of oil quality sensor216.

As noted first PZT crystal 401 is shaped as a ring, and a second PZTcrystal 402 is a disk are set into pockets within acoustic lens 412.Lens 412 is most preferably constructed of peek or ULTEM plastic, due tothe materials high heat resistance, hardness and toughness.Alternatively, the lens 412 can be molded from an appropriate hightemperature resisting epoxy material, and potted with accompanying partsin a single layup. Acoustic lens 412 in a preferred embodiment has aplanar face 416, in certain applications it can have a concave face. Theplanar face 416 generates a cylindrical or collimated focal zone tomonitor a larger sample volume; whereas the concave lens face generatesa converged focus as the general concept is commonly understood in theart. More specifically, in contrast to prior art or other methods, thepurpose of this embodiment is to not fully focus the acousticinterrogation pulse to an infinitesimally small volume, but tostrategically concentrate acoustic energy within the target zone whichis a finite and substantial volume. Thus, for example, the portion oflens 416 over element 401 when used as the interrogation function canassume an optimal combination of spherical, conical, or parabolicgeometry that is known in the art to concentrate acoustic waves at adistance from the transducer face. Also, the region of lens 416 overelement 402 when used as the receiver can remain flat, to provideoptimal sensitivity to return echoes. As a further refinement one mayemploy a partially focused concave lens embodiment, since the acousticgradient of focus intensity will naturally increase towards the back ofthe target volume. This will compensate for the tendency for the returnecho from a potential target that naturally attenuates with distance.Thus, an optimized partially-focused interrogation can compensate forthis distance to provide more uniform return signal amplitude throughoutthe target zone. This method eliminates a time variable that otherwisemust be compensated for by the particle sizing algorithm.

Dampening element 422 is fitted to the inboard side of a first PZTCrystal 401 and dampening element 424 is fitted to the inboard side ofsecond PZT Crystal 402. The dampening elements attenuate the crystalring down signal 314 of the interrogation pulses; the PZT crystal(s) canotherwise exhibit an extended vibration period and generate acousticnoise such that the received acoustic signal is corrupted. Dampeningelement 422 is configured as a tube; dampening element 424 is configuredas a cylinder. Appropriate materials for the dampening elements areknown in the art as typically consisting of mixtures of an epoxy matrixand granules of a dense material such as tungsten. The granules augmentthe dampening process since they absorb, deflect and scatter acousticwaves. The distal end of each dampening element is shaped to furtherprovide a dampening effect. Damping element 424 has a v-notched profilegroove 440. The damping element 422 also has a V-notched groove 444. Inthe preferred embodiment the geometry of each of the groves 440 and 444is an acute angle under 45 degrees between the sides of the groves. Thisfeature radially deflects the axially propagating residual acousticinterrogation wave to limit its reflection back to the PZT crystalelement. The dampening elements are configured to not directly contactone another, which prevents signal cross-contamination. As noted PZTcrystals 401 and 402 are electrically connected to connector 428 with alow-gauge cables 430A and 430B with techniques common to the art. Thecables can be routed through void 449. Acoustic lens 412, PZT crystals401 and 402, and dampening elements 440 and 444 are bonded together withan appropriate high temperature resisting epoxy. The epoxy also pots andencapsulates the crystal-side terminal ends of cables. Acoustic lens 412is bonded into tube 432. Connector 428 can be bonded into, screwed into,or constrained with a set screw to tube 432. As an alternative the voidor open space 449 at the back of transducer 400 and between dampeningelements 424 and 444 and casing 432 can also be filled with additionaldampening materials such as a high viscosity fluid.

FIG. 4C provide a cross-sectional view of an alternative preferredembodiment 460. In this variation all the elements are the same as thoseon embodiment 400 depicted in FIGS. 4A and 4B with one exception.Dampening element 451 attached to the inboard side of PZT crystal 402 isa relatively thin disk in contrast to a cylinder or rod 422 of crystal401. Thin disk 451 increase the sensitivity of crystal 402 for receptionof reflected or echo waves. In this variation of the transducer 460 PZTcrystal 401 generates interrogation pulses and PZT crystal 402 receivesthe echo or reflected Ultrasonic waves. The small dampening element 451increases the sensitivity of crystal 402 by not over dampening the echoor reflected return signal. FIG. 4D provides a cross sectional view ofanother embodiment of the transducer of the present invention 470. Inthis variation all of the elements are the same as those in theembodiment 400 and numbered the same except dampening element 471 isattached to transducer crystal 401. The small dampening element 471attached to transducer 401 increases the sensitivity of transducercrystal 401 to incoming echoes or reflected ultrasonic waves. Thus, inthis embodiment crystal 402 transmits the ultrasonic pulses and crystal401 is the receiver, and receives the reflected echo.

FIGS. 4E and 4F illustrate yet another embodiment of the transducer. Inthis variation all of the elements are the same as those depicted inFIGS. 4A and 4B and numbered the same with the exception that transducerlens 412 has been eliminated and only an isolating acoustic insulatingring 485 is positioned between crystals 401 and 402 to acousticallyisolate them. In contrast, the embodiments of 4A, 4B, 4C, and 4D allutilize a shared lens 412, 416. However, this results in a degree ofacoustic contamination of the receiver portion. This will require alonger ring down time to provide an acoustically clean reception field,and hence the transducer will need to be placed further from the targetzone. On the other hand this embodiment can share the return echo sinceeven if the echo impinges with the transmit portion of lens 416, somereturn signal is obtained. There is a tradeoff in the effect betweenversions 4E, 4F and versions 4A, 4B, 4C, and 4D. The latter can beplaced closer, get a stronger return echo but miss part of it.

A Method for Implementation:

A Method to implement the invention is illustrated in FIG. 5 is a simpleflow chart that summarizes one preferred method the system uses toanalyze and organize the data collected by the sensors described above.These routines consist of ultrasonic debris sensing routine 501,inductive sensing routine 503 and oil quality sensing routine 505.

Regarding routine 501 at step 511 the ultrasonic sensing routine asconducted by the Acoustic Debris Monitor (ADM) (the proposed trade namefor the ultrasonic transducer of the present invention) periodicallytransmits a signal at an oblique angle towards path along which thedebris particles are moving. Reflected echoes from particles or airbubbles are received the by transducer described above. Computer 157operating with appropriately software based on the readings receiveddetermines if the particle moving through its field of view is a solidparticle or an air bubble it determines the size of the particle andcollects the information on size and count for tabulation 512. Theroutine also time stamps each particle and sends 515 this information toinductive routine 521. At step 517 the system can include the step ofcomparing the count calculations and size of the particles to a storedminimum count and threshold size. If the particle count or particle sizereaches a threshold count and size the system can signal an alarmcondition.

Inductive sensor routine 503 upon receiving the time stamped informationfrom the ultrasonic debris sensing routine 501, determines, based on theflow characteristics of the fluid, when the time stamped particle shouldbe moving through the field created by the inductive sensor. If itcannot detect the particle it determines it is non-metallic 523. If theparticle is metallic, the inductive sensor detects its presence anddetermines if it is ferrous or non-ferrous 524. At step 529 based on thetime stamp of the event identifying each particle the information iscollected and collated as non-metallic, metallic non-ferrous, or ferrousparticles. The information is also tabulated at step 529 with theinformation obtained by routine 501.

Additionally, running in parallel is fluid quality sensor routine 505,which based on the conductivity and polarity readings is assessing themoisture content and oxidation of the fluid or other aspects of thefluid depending on the fluid system being monitored 527. The routineprogrammed at step 527 could include in an oil lubrication system analert if the water content of the oil exceed a certain threshold such as50%. Depending on the system if water reaches a certain thresholdpercentage it will start to come out of solution and corrode thebearings or other metal parts of the system. The information from thefluid quality routine is collected and tabulated with the otherinformation 529. All of this information then provides criticalinformation regarding the condition of the fluid in the system underobservation. In the preferred embodiment of the sensor at 505 is apolymer bead matrix sensor.

Although the description of the invention herein uses the example of anoil lubrication system in describing the invention at various points inthis disclosure, the system can be used for the monitoring of thecondition of a wide variety of fluid circulating systems or liquidstream systems. Not to limit the applicability of the invention asdescribed herein it could be used in a soft drink production plant, abrewery, milk processing system, ice cream production plant, a publicdrinking water system or any other of a number of systems or plants thatneed to monitor the quality and condition of a liquid flow or liquidstream. For example the system of the present invention could be usedfor measuring the CO₂ bubble size and amount in a brewery or sodaprocessing plant. A bleeder tube or exit port could be added to thebottom of the sensor array and the flow of the fluid through the sensorarray circulated back to the main flow to count air or CO₂ bubbles anddetermine size. The concept of passing the fluid through the sensorarray and then recirculating the fluid back to the main flow of fluidcould be uses with other fluid flows.

A Method for Creating Fusion-Neural Network Monitoring System

Wear debris (acoustic and inductive) and water content signals aremerged by data fusion technology to learn and classify failure modes ofthe lubrication machinery such as a gearbox. Data fusion is used toimprove the performance of the diagnosis capability. It can also performinferences that are not possible from a single sensor alone. Because ofthe diversity of failure type, several kinds of quantities are used thatare effective for identifying different failures. Measurements takenusing single sources are not fully reliable and are often incomplete dueto the operating range and limitations that characterize each sensor. Inaddition, sensor signals can be corrupted by noise or can malfunctionall together. Fusing their measurements can provide a more robust andreliable reading than that from any one sensor since signals tend to becorrelated between sensors whereas noise is uncorrelated.

Fusion methods include Neural Networks such as the Radial Basis FunctionNetwork and Backpropagation Network. The advantage of using neuralnetworks is that they can handle non-linear correlations involvingsudden transitions or complicated interactions among input variables.They are also robust to sensor noise and malfunctions. The neuralnetwork is trained by first inputting known fluid measurements (trainingset) for a range of known good and bad conditions and training thenetwork to recognize these cases. The training set consists of a set ofsensor features. The features are generated by processing the individualraw sensor signals and extracting pertinent data about the state of thefluid. The features include particle counts, particle size, particlematerial, particle distribution changing rate, water content, oiltemperature, etc. Once the network is trained it can be applied to a newset of fluid measurements and provide a means of analyzing data andrelating the new measurements to learned failure modes of the machinery.

A Preferred Embodiment of the Cyclonic Separator:

FIG. 6 provides a top view of a preferred embodiment of a cyclonicseparator 600 according to the present invention; with the top partiallycut away to provide a partial view of the interior. FIG. 7 is a cut-awayside view of separator 600 along line VII-VII on FIG. 6 in the directionof the arrows.

Referring to FIG. 7 inlet port 604 is at an offset position from thecenter axis 601 of separator 600 and located near the top 607 of theinterior. Outlet port 609 is located at the top center of the separator.Referring to FIG. 6 and FIG. 7 collection channel 620 is located in thefloor 610 of the separator 600 and makes a complete circuit around thefloor 610 adjacent to the inner wall 608 with the exception of diversionturn 621 where channel 620 diverges from wall 608 and connects tocollection port 642 which leads into the sensor array channel 617, theposition of which is under the separator and indicated by the outline645. Since sensory array channel 617 ends in a dead-end the fluid insensory array channel 617 is substantially still or stagnant.

Referring again to FIG. 7 the positions of inlet port 604 and outletport 609 can be seen. Outlet port 609 is coextensive with flow divider630. The inner wall 608 makes an acute angle 603 with the floor 610 ofseparator 600. A portion of collection channel 620 can be seen on theright side adjacent to the wall 608 and in the diversion turn 621 areaon the left where it meets collection port 642 which creates an openinginto the sensor array 207. Additionally, cyclonic separator 600 in FIG.7 is in the position it would normally be operating with thegravitational field being downwards as depicted by arrow 657.

As can be seen from FIGS. 6 and 7 the shape of the interior 602 ofcyclonic separator 600 is a truncated conic section, where the top 607is circular in shape and has a smaller diameter than floor 610 whichalso has a circular shape. Top 607 and floor or bottom 610 are connectedby continuous wall 608. Thus, the ideal interior shape is a conicsection cut by two parallel planes, which intersect at right angles thecentral axis of the conic section. This creates the truncated conicsection which looks like an inverted pie dish or pan.

Referring to FIG. 6 fluid entering cyclonic separator at inlet 604 inthe direction of arrow 605 hits interior wall 608 and is diverted in acircular path 660. As more fluid enters it continues in a circular flowand is forced downwards into the interior of chamber 602. Particulatematter 102 is forced out to the edge of the chamber and eventually fallsinto collection channel 620. The particulate matter 102 then is movedalong collection channel 620 where it eventually falls through drop port642 into the sensor array 207 where its composition and size isdetermined by the sensor array 207 as described above in detail. Thefluid circulation in cyclonic separator 600 is eventually forced outthrough outlet 609. Given the higher pressure in the fluid along thewall air bubbles in the fluid will also tend to be forced to the centerand out through outlet 609. Deflection mound 640 prevents particulatedebris 102 from collecting in the bottom center of separator 600.Diversion turn 621 of collection channel 620 allows for the placement ofsensor array directly under cyclonic separator 600 and thus prevents itfrom protruding beyond the profile of the separator bounded by dashedline 611. The system of the present invention, including the cyclonicseparator 600 can be used in a wide variety of systems to analyze anddetermine the condition of fluid flowing in a system. This can vary fromfluid flow systems of soda plants and breweries to the oil circulatingsystems of helicopters and fighter jets. The ability to provide acompact package of the system is often an important feature.

Referring to FIGS. 7 and 7A inlet flow channel 675 indicated in outlineform progresses in smooth transition from a circular inlet port 604 toan elliptical opening 677 into the interior chamber 602 near the top ofinterior 607 of separator 600. Thus channel 675 progresses from a roundchannel to an elliptically shaped channel where in the preferredembodiment the cross sectional area of the channel remains roughly thesame from the round inlet to the elliptical outlet. Inlet channel 675enters at a tangent to the curve of the interior wall 608 so an openportion 678 of inlet channel 675 continues in the wall 608 to completethe open extension of the channel 675 in wall 608. The shape of inletchannel 675 as described results in fluid flowing in channel 675entering in a smooth laminar flow and avoiding a turbulent chopping flowof fluid into interior 602. Acute angle 603 forces fluid in top ofinterior 607 downwards and radially outwards away from the outlet toprevent the turbulent mixing of the particle laden inlet flow with theclean outlet flow. The geometry is so effective that flow divider 630 insome instances may not be necessary.

Another Variation of the Cyclonic Separator:

FIGS. 8 and 9 provide another variation of the cyclonic separator of thepresent invention. The variation of the cyclonic separator 800 in FIG. 8is similar in some respects at that depicted in FIGS. 6 and 7.Accordingly, when the feature of separator 800 is the same as separator600 the same reference number will be used. When it is different adifferent reference number will be used.

Referring to FIG. 8 cyclonic separator 800 is depicted in its uprightposition, in the orientation it would have when it is in use. Thegravitational field 657 being in the down direction. Inlet port 604 andoutlet port 609 are visible. Additionally, from the cut-away view on thelower right side, a portion of collection channel 820 can be seen withthe rest of channel 820 appearing in outline form. Sensor array 207attaches to tangential extension 842 of collector channel 820. Thustangential extension 842 acts as a collector port. As noted above acuteangle 603 forces fluid in top of interior 607 downwards and radiallyoutwards away from the outlet to prevent the turbulent mixing of theparticle laden inlet flow with the clean outlet flow. The geometry is soeffective that flow divider 630 in some instances may not be necessary.

FIG. 9 is a cross-sectional view of separator 800 in FIG. 8 along lineIX-IX in the direction of the arrows. Inlet port 604 and outlet port 609can be seen. Top of interior 607 connects to continuous wall 608.Continuous wall 608 connects to bottom 610 to form the truncated conicsection (the same shape as in the previous embodiment) which has theshape of an inverted pie plate or pan. In this variation collectionchannel 820 circumscribes the entire edge of floor 610 where it meetswall 608. Deflection mound 640 is in the center. In FIG. 9 the positionof sensor array 207 is shown in outline to indicate its position on inthe side profile view shown in FIG. 9.

The embodiment of the invention depicted in FIGS. 8 and 9 functions in asimilar fashion as that depicted in FIGS. 6 and 7. Referring to FIG. 8,the fluid enters cyclonic separator through inlet 604. It then flows ina circular clockwise flow around axis 601 of separator 800. Given thetruncated conic shape the flow is forced down along wall 608 towardfloor 610 and then when it passes below the inside bottom edge of flowdivider 630 is forced out through outlet 609. Particulate matter 102 isforced down into collector channel 820 and then out collector port 842into sensor array 207. In this embodiment, in contrast to the embodimentof FIGS. 6 & 7, by virtue of the flow geometry, the particles are sweptdirectly into collection port 842.

The discussion of sensor array 207 above describes what happens onceparticulate matter 102 is directed into sensor array 207.

A 3-D printing process is particularly applicable for the manufacture ofembodiments 600 and 800 of the cyclonic separator. 3-D printing isavailable in polymer and metal materials. The latter is available inaerospace-appropriate materials such as Titanium, Aluminum, andStainless Steel. A 3-D printed version can achieve a seamlessconstruction. Such a construction would simplify the construction andlower the unit's bulk and weight by eliminating a seam, a seal, andfasteners. Moreover, in regard to conventional molding processes, theelliptical-transitioned inlet depicted in FIG. 7A could prove to beinfeasible to mold while using conventional methods. 3-D printing, asopposed to conventional molding, allows undercuts and do not requiredraft angles that are otherwise needed to eject the part from the mold.A seamless unit eliminates leak-prone seams and thus represents a morereliable approach. A seamless unit would thus most likely be a singleunitary structure wherein all of the surfaces and ports are built intoone structure with no seams of separate parts. Both of the preferredembodiments described above and depicted in FIGS. 6, 7, 7A, 8 and 9 canbe manufactured by a 3-D manufacturing method to achieve the desiredshape.

Tabulation of Information:

FIG. 10 provides a sensor output histograms of information generated bythe apparatus and system of the present invention. Three differenthistograms are shown, for cumulative particle count 1001, cumulativebubble count 1003 and cumulative metallic particles count 1005.

Each histogram has different size categories of particles presentedalong the x-axis and the particle count is shown on the y-axis. Thehigher the column on the y-axis the more particles or bubbles of theparticular size category, which ranges from 50 microns to 1000+ microns.The first category being 50 to 100 microns. The second 100 to 250microns, etc. The size ranges can be adapted to the particularapplication.

Monitoring Display:

FIG. 11 provides an embodiment of a system output display 1110, whichmight constitute part of an aircraft multi-sensor contaminationmonitoring system that employs the present invention. The systemincludes a dial for debris particle count 1125, a dial for debris size1130, and a three part gauge that breaks down the particle count toferrous 1140, metallic non-ferrous 1150 and non-metallic 1160. Thesystem also includes a dial for oxidation 1180 and a dial for watersaturation 1170 from the oil quality sensor.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is no way intended thatany particular order be inferred.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention. Since modifications combinations,sub-combinations and variations of the disclosed embodimentsincorporating the spirit and substance of the invention may occur topersons skilled in the art, the invention should be construed to includeeverything within the scope of the appended claims and theirequivalents.

The invention claimed is:
 1. A method for monitoring and analyzing thecondition of a fluid flow comprising the steps of: a. separatingparticulate matter from a primary fluid flow channel; b. directingobjects in the fluid flow to a sensor array so that the objectspass-along a predetermined path in a substantially still portion of thefluid of the fluid flow; c. interrogating a predetermined field of viewalong the predetermined path with a plurality of partially focusedultrasonic pulses directed along an axis of transmission at an obliqueangle to said predetermined path and receiving reflections of ultrasonicpulses from the objects wherein said reflections of ultrasonic pulsesare on an axis of reception congruent with the axis of transmission ofsaid ultrasonic pulses; d. generating an inductive field along saidpredetermined path; e. distinguishing air bubbles from particulatematter among the objects detected based on a received plurality ofreflections; f. determining a size of the objects; g. determining if theparticle is metallic or non-metallic by combining readings from theultrasonic reflections and inductive field readings; and h. determiningif a metallic particle is ferrous or non-ferrous from the inductivefield readings.
 2. The method of claim 1 comprising the further step ofdetermining the condition of the fluid.
 3. The method of claim 1 whereinsaid fluid flowing being monitored is selected from a group of fluidsconsisting of: beer, wine, milk, ice cream, water, soda, coffee,espresso, chocolate and cocoa.
 4. The method of claim 2 wherein the stepof determining the condition of the fluid is selected from a groupconsisting of: the moisture content of the fluid, the oxidation of thefluid, and the size of carbon dioxide bubbles in the fluid.
 5. Themethod of claim 2 wherein the step of determining the condition of thefluid is done with a polymer matrix sensor.